Liner board or paper



Patented June 24, 1930 mas-6e I ALBERT L, CLAPP, OF"DAN VE BS, MASSACHUSETTS LINER mean on PAPER,

Zlt'o Drawing.

In the manufacture of paper or card-board of the kind known commercially as patent coated, such as used in the manufacture of cartons, boxes, containersand for other uses,

. it is customary by a suitable coating machine to apply to a sheet of formed and dried paper or board, a surface coating of china clay, blanc fixe or other surfacing material, and casein or other like adhesive.

The object of the inventionv is to provide a I liner paper or board having a surface coating of china clay, blanc fixe or other equivalent material to impart a smooth or satinyfinish, and to produce the same at one operation in a paper machine. I

I have made the discovery that kiesel-guhr or f cellite, and wood flour, either separately or m combination, havethe property or capaclty, when suspended in water, of being formed on machine and of being transferred to a makeup roll or blanket thereof, although the layer or layers thus placed or built up on the makeup roll or blanket cannot be removed as a web or sheet as they have no tensile strength.

I have also discovered that these two substances also have the property of carrying with them a large or dominant quantity of china clay, blanc fixe or other pulverulent 3o coating materials. As a result of these two discoveries, I have found from prolongedexperlmentation that it is possible to apply to a layer of paper or board, while it is being formed and 1s still in a wet state, a lay of cellite or wood flour or both, and the prev1ously-ment1oned coating materials, so that, when the composite sheet is dried, it possesses the deslrable characteristics of the pat,- ent coated paper or board.

In carrying out my invention, Iuse a 'mul tlple-cyhnder paper machine having the proper vats associated withthe several cylinders and transfer rolls. In one of the vats I placeany suitable paper stock such as may 46 be required for producing the desired paper the cylinder mold of a paper Application filed December 22, 1922: Serial No. 608,579.

or board, and in another vat I place an aqueous suspension of cellite and/or wood flour and a dominantproportion of the desired filler or coating substance. {Ihen to the wet web of the paper stock, tramsferred to the 50 blanket or belt of the machine, I apply a layer of the stock in the second vat, or vice versa, so that a composite Web or sheet is formed which is dried in the usual manner, with the result that the finished producthas an adherent topsurface or layer of the coating substance.

In carrying out my invention, one may proceed as follows: In a beating engine, I prepare a suitable pulp by vigorously beating together 50 parts, by weight, of mixed waste paper and an equal amount of bleached sulphite pulp. When this has been accomplished; I add 5 parts of rosin size, and, when this has been thoroughly brushed (it into the pulp, I add 5 parts of alum and continue the beating until reaction has been accomplished. In another beating engine I place 10 parts, by weight, of cellite or kieselguhr, 20 parts of wood flour, and parts of 70 china clay, together with water to form a suspension. These are beaten or agitated until a suspension is produced which will form on thecylinder mold of a paper machine. Then into two separate vats of a multiplecylinder paper machine are placed the stocks produced asv hereinbefore, provided, and a composite web is formed consisting of a layer or web of fiber and a faeially contiguous adherent layer of kieselguhr-wood flour-clay so mixture. The wet web or sheet is now treated in the usual manner followed in the manufacture of paper, being dried, calendered and wound into rolls. On being dried and calendered, the sheet hasv a surfacelayer comprising about 70% of china clay and 30% of the carrier.

Obviously it is unnecessary that the fibrous lamination or bottom layer of the fibrous sheet should be sized, and consequently, in

the formation of the pulp, the size may be omitted. Again, I should not regard it as a departure from the invention if the top layer should contain some fibers and/or a size. Thus, in the formation of the stock for the top layer, I may use:

5 to 20 parts bleached sulphite pulp,

10 to 20 parts wood flour,

10 to 20 parts cellite,

50 to 70 parts china clay,

10 parts silicate of soda (or rosin size),

5 parts alum.

In such case, one may vigorously beat together in a beating engine the sulphite pulp and the wood flour with water for about an hour, after which the cellite and the china clay are added and. the'stock beaten for a further period of about 30 minutes. Then the sillicate of soda is thoroughly incorporated in the stock, and finally the alum is added, after which the stock is brushed out for about anhour. The sodium silicate 01' sodium resinate is precipitated as alumi-' num silicate or aluminum resinate by the alum, and constitutes a gelatinous size which coagulates and asslsts m retammg the china clay.

Of course I do not limit myself to the use of china clay in the formation of the top layer, as any equivalent pulverulent material may be used, such, for example, as blanc fixe, pulverized rosin or carbon black, or other finely powdered pigments.

A composite sheet as herein described forms perfectly and the laminations or layers adhere or interlock most satisfactorily.

I am not familiar with any generic name,

otherthan the term carrier or words of similar import, which can be applied to wood flour and kieselguhr or cellite. Either of these materials or both in combination have the properties hereinbefore described of forming on the cylinder mold and of being transferred as a continuous layer to the blanket or felt of a paper machine and act as earners in carryin or absorbing many times their weight of pu @rulent material in their Due to the lack of a better' formation.

term, I desire to havejt understood that in the claims, whenever I refer to carrier I I mean either kieselguhr or wood flour alone or in admixture.

I also desire to be understod that the bottom fibrous layer of the composite web or sheet may be made of any approved fibrous or cellulosic materials (sized or unsized as oocaslon demands) which it may be desired to use in the formation of any predetermined form of board or paper, the examples which I have herem given being illustrative of composite webs embodying the invention and of the new or improved process which may be practiced in their production.

1le I have herein referred to the use of character has the property of forming on a cylinder mold, although in my opinion the results are not quite as satisfactory when finely-divided sawdust is used as when wood flour is used.

It is further obvious that, while I have referred to an exterior layer of china clay or blanc fixe, carbon black, or finely-divided pigments, the process as herein described includes the use-of any finely-divided or pulverized material of the character of resins, pigments, gums or the like; so that, in referring to a pulverulent material such as china clay or the like, I mean to include pulverulent substances of the character of all of those herein referred to which it-may be desired to employ in the formation of the top layer of the sheet.

What I claim is I 1. A composite sheet comprising a bottom layer of cellulosic material, and a top layer comprising a mixture of pulverulent coating material, and kieselguhr.

2. A composite sheet comprising a bottom layer of cellulosic material, and a top layer comprising a mixture of a'small proportion of kieselguhr and a dominant proportion of pulverulent coating material.

3. A composite sheet comprising a bottom layer of cellulosic material, and a top layer comprising a mixture of a small proportion of kieselguhr, a precipitate, and a dominant proportion of pulverulent coating material.

4. A process of producing a sheet having a surface layer of a pulverulent material, which comprises forming a web of pulp, independently forming a substantially nonfibrous Web from an aqueous suspension of the pulverulent material carried by a finely divided carrier, and applying it as a contiguous adhering layer to said web of pulp, and then simultaneously removing the water from both webs.

5. A. process of producing a sheet having a surface layer of a pulverulent material, which comprises forming on independent cylinder molds and uniting a web of cellulose pulp and asubstantiallynon-fibrous web of pulverulent material carried by a finely divided carrier capable by itself of forming on the cylinder mold, and drying the sheet.

6. A process which comprises forming into contiguous, adherent webs on a multi-. ple cylinder machine, a web of cellulose pulp and a substantially non-fibrous web of a finewood flour, which is a finely-disintegratedly divided material carrying a preponderant messed proportion of pulverulent material, and drying the sheet thus produced. I 1

7 A process which comprises forming into contiguous, adherent webs on a multiple cylinder machine, a web of cellulose pulp and a substantially non-fibrous web of a finely divided material carrying a size and a -pre ponderant proportion of pulverulent material and drying the sheet thus produced.

8. A process which comprises forming into contiguous, adherent webs on a cylinder machine, a web of cellulose pulp and a web comprising onlya small portion of fibrous material, size, and a finely divided material, carrying a preponderant proportion ot a pulverulent material; and drying the sheet thus produced. I

9. A process of producing a paper having a surface layer of pulverulent coating material, which comprises forming'a web of pulp, independently forming a substantially non-fibrous web of kieselguhr carrying a preponderant proportion of the coating material, applying said second-mentioned Web as a continuous adherent layer to thesweb of pulp, and drying the web.

10. A composite sheet comprising a bottom layer of cellulose fiber, and a top layer comprising a mixture of china clay and kieselguhr.

In testimony whereof I have afixed my signature.

ALBERT L. QLAPR 

